Efficient Production of -Caproate From Syngas by a Co-culture of Clostridium Aceticum and Clostridium Kluyveri

Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG[Abstract] In recent years, the possibility of merging technologies for waste recovery such as those based on syngas fermentation and chain elongation has been studied for the production of medium chain fatty acids (MCFAs) and bioalcohols, in an attempt to integrate the concept of circular economy in the industry. Nevertheless, one of the main issues of this approach is the pH mismatch between acetogens and chain elongating microorganisms. This work reports, for the first time, the suitability of a co-culture of C. aceticum and C. kluyveri metabolizing syngas at near neutral pH in stirred tank bioreactors. For this purpose, bioreactor studies were carried out with continuous syngas supply. In the first experiment, maximum concentrations of -butyrate and -caproate of 7.0 and 8.2 g/L, respectively, were obtained. In the second experiment, considerable amounts of -butanol were produced as a result of the reduction, by C. aceticum, of the carboxylates already formed in the broth. In both experiments, ethanol was used as an exogenous electron agent at some point. Finally, batch bottle assays were performed with a pure culture of C. aceticum grown on CO in presence of n-butyrate to assess and confirm its ability to produce -butanol, reaching concentrations up to 951 mg/L, with a -butyrate conversion efficiency of 96%, which had never been reported before in this species. Therefore, this work contributes to the state of the art, presenting a novel system for the bioproduction of MCFAs by combining syngas fermentation and chain elongation at near neutral pH, as opposed to the acidic pH range used in all previously reported literature.This research was funded through the Spanish Ministry of Science and Innovation and European FEDER funds (PID2020-117805RB-I00). CFB thanks Xunta de Galicia for her doctoral contract (ED481A-2020/028). The authors, belonging to the BIOENGIN group, thank Xunta de Galicia for financial support to Competitive Reference Research Groups (ED431C 2021/55). Funding for open access charge provided by Universidade da Coruña/CISUGXunta de Galicia; ED481A-2020/028Xunta de Galicia; ED431C 2021/5

Factors Affecting the Optimisation and Scale-up of Lipid Accumulation in Oleaginous Yeasts for Sustainable Biofuels Production

Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG[Abstract] The recent unprecedented increase in energy demand has led to a growing interest in emerging alternatives such as the production of microbial lipids with high energy density and environmentally-friendly characteristics. Oleaginous yeasts represent a versatile and attractive tool for the accumulation of such lipids, also known as single cell oils (SCOs), used to manufacture biofuels (e.g., biodiesel, aviation fuel) and bioproducts. This review provides an overview of the most common oleaginous species, analysing the viability of typical feedstocks and their effect on lipid accumulation. The best results in terms of lipid content using glucose, glycerol, lignocellulose, or acetic acid as substrates are 81.4, 70, 68.2 and 73.4% (w/w), respectively. Besides, an analysis of the parameters that can affect lipid production is also presented. For instance, the optimum conditions for lipid accumulation are usually a C/N ratio between 100 and 200, pH between 5 and 6 (being more alkaline if acids are used as substrates) and temperature around 30 °C. Besides, genetic modifications generally allow to increase the lipid yield, even by up to 400%. Finally, some cost analysis is provided for scaling-up, with feedstock costs estimated at 50–80%, followed by fermenter costs, and downstream costs estimated at around 13%.This study was funded by the Spanish Ministry of Science and Innovation and European FEDER funds (PID2020-117805RB-I00). The manuscript is based on research related to COST action Yeast4Bio. RR thanks the Ministry of Science and Innovation for financial support of his doctoral research (E-15-2019-0344365). CFB (ED481A-2020/028) thanks Xunta de Galicia for financing her doctoral research. The authors, belonging to the BIOENGIN group, thank Xunta de Galicia for financial support to Competitive Reference Research Groups (ED431C 2021/55)Xunta de Galicia; ED481A-2020/028Xunta de Galicia; ED431C 2021/5

Effect of pH and medium composition on chain elongation with Megasphaera hexanoica producing C4-C8 fatty acids

IntroductionChain elongation technology, which involves fermentation with anaerobic bacteria, has gained attention for converting short and medium chain substrates into valuable and longer-chain products like medium chain fatty acids (MCFAs). In the recent past, the focus of studies with pure chain elongating cultures was on species of other genera, mainly Clostridium kluyveri. Recently, other chain elongators have been isolated that deserve further research, such as Megasphaera hexanoica.MethodsIn this study, batch studies were performed in bottles with two different media to establish the optimal conditions for growth of M. hexanoica: (a) a medium rich in different sources of nitrogen and (b) a medium whose only source of nitrogen is yeast extract. Also, batch bioreactor studies at pH values of 5.8, 6.5 and 7.2 were set up to study the fermentation of lactate (i.e., electron donor) and acetate (i.e., electron acceptor) by M. hexanoica.Results and discussionBatch bottle studies revealed the yeast extract (YE) containing medium as the most promising in terms of production/cost ratio, producing n-caproate rapidly up to 2.62 ± 0.24 g/L. Subsequent bioreactor experiments at pH 5.8, 6.5, and 7.2 confirmed consistent production profiles, yielding C4-C8 fatty acids. A fourth bioreactor experiment at pH 6.5 and doubling both lactate and acetate concentrations enhanced MCFA production, resulting in 3.7 g/L n-caproate and 1.5 g/L n-caprylate. H2 and CO2 production was observed in all fermentations, being especially high under the increased substrate conditions. Overall, this study provides insights into M. hexanoica’s behavior in lactate-based chain elongation and highlights optimization potential for improved productivity

N2O and CH4 fluxes in Undisturbed and Burned Holm oak, Scots pine and Pyrenean oak forests in Central Spain

We investigated N2O and CH4 fluxes from soils of Quercus ilex, Quercus pyrenaica and Pinus sylvestris stands located in the surrounding area of Madrid (Spain). The fluxes were measured for 18 months from both mature stands and post fire stands using the static chamber technique. Simultaneously with gas fluxes, soil temperature, soil water content, soil C and soil N were measured in the stands. Nitrous oxide fluxes ranged from −11.43 to 8.34 μg N2O–N m−2 h−1 in Q.ilex, −7.74 to 13.52 μg N2O–N m−2 h−1 in Q. pyrenaica and −28.17 to 21.89 μg N2O–N m−2 h−1 in P. sylvestris. Fluxes of CH4 ranged from −8.12 to 4.11 μg CH4–C m−2 h−1 in Q.ilex, −7.74 to 3.0 μg CH4–C m−2 h−1 in Q. pyrenaica and −24.46 to 6.07 μg CH4–C m−2 h−1 in P. sylvestris. Seasonal differences were detected; N2O fluxes being higher in wet months whereas N2O fluxes declined in dry months. Net consumption of N2O was related to low N availability, high soil C contents, high soil temperatures and low moisture content. Fire decreased N2O fluxes in spring. N2O emissions were closely correlated with previous day’s rainfall and soil moisture. Our ecosystems generally were a sink for methane in the dry season and a source of CH4 during wet months. The available water in the soil influenced the observed seasonal trend. The burned sites showed higher CH4 oxidation rates in Q. ilex, and lower rates in P. sylvestris. Overall, the data suggest that fire alters both N2O and CH4 fluxes. However, the magnitude of such variation depends on the site, soil characteristics and seasonal climatic conditions

The Characteristics of the HIV-1 Env Glycoprotein Are Linked With Viral Pathogenesis

The understanding of HIV-1 pathogenesis and clinical progression is incomplete due to the variable contribution of host, immune, and viral factors. The involvement of viral factors has been investigated in extreme clinical phenotypes from rapid progressors to long-term non-progressors (LTNPs). Among HIV-1 proteins, the envelope glycoprotein complex (Env) has been concentrated on in many studies for its important role in the immune response and in the first steps of viral replication. In this study, we analyzed the contribution of 41 Envs from 24 patients with different clinical progression rates and viral loads (VLs), LTNP-Elite Controllers (LTNP-ECs); Viremic LTNPs (vLTNPs), and non-controller individuals contemporary to LTNPs or recent, named Old and Modern progressors. We studied the Env expression, the fusion and cell-to-cell transfer capacities, as well as viral infectivity. The sequence and phylogenetic analysis of Envs were also performed. In every functional characteristic, the Envs from subjects with viral control (LTNP-ECs and vLTNPs) showed significant lower performance compared to those from the progressor individuals (Old and Modern). Regarding sequence analysis, the variable loops of the gp120 subunit of the Env (i.e., V2, V4, and mainly V5) of the progressor individuals showed longer and more glycosylated sequences than controller subjects. Therefore, HIV-1 Envs from virus of patients presenting viremic control and the non-progressor clinical phenotype showed poor viral functions and shorter sequences, whereas functional Envs were associated with virus of patients lacking virological control and with progressor clinical phenotypes. These correlations support the role of Env genotypic and phenotypic characteristics in the in vivo HIV-1 infection and pathogenesis.This work is supported by Spanish AIDS network “Red Temática Cooperativa de Investigación en SIDA” RD12/0017/0002, RD12/0017/0028, RD12/0017/0034, RD16/0025/0011, RDCIII16/0002/0005, and RD16/0025/0041 as part of the Plan Nacional R + D + I and cofunded by Spanish “Instituto de Salud Carlos III (ISCIII)-Subdirección General de Evaluación y el Fondo Europeo de Desarrollo Regional (FEDER).” JB is a researcher from “Fundació Institut de Recerca en Ciències de la Salut Germans Trias i Pujol” supported by the Health Department of the Catalan Government/Generalitat de Catalunya and ISCIII grant numbers PI17/01318 and PI20/00093 (to JB). Work in CL-G and CC lab was supported by grants SAF (2010-17226) and (2016-77894-R) from MINECO (Spain) and FIS (PI 13/02269 and PI20/00093, ISCIII). AV-F’s Lab is supported by the European Regional Development Fund (ERDF), RTI2018-093747-B-100 (“Ministerio de Ciencia e Innovación,” Spain), “Ministerio de Ciencia, Innovación y Universidades” (Spain), ProID2020010093 (“Agencia Canaria de Investigación, Innovación y Sociedad de la Información” and European Social Fund), UNLL10-3E-783 (ERDF and “Fundación CajaCanarias”) and “SEGAI-ULL.” SP-Y is funded by “Fundación Doctor Manuel Morales” (La Palma, Spain) and “Contrato Predoctoral Ministerio-ULL Formación de Doctores” (2019 Program; “Ministerio de Ciencia, Innovación y Universidades,” Spain). RC-R is funded by RD16/0025/0011 and ProID2020010093 (“Agencia Canaria de Investigación, Innovación y Sociedad de la Información” and European Social Fund). JE-H is funded by the Cabildo Tenerife “Agustin de Betancourt” 2017 Program.S

Genotype–phenotype correlation in patients with Usher syndrome and pathogenic variants in MYO7A: implications for future clinical trials

Purpose: We aimed to establish correlations between the clinical features of a cohort of Usher syndrome (USH) patients with pathogenic variants in MYO7A, type of pathogenic variant, and location on the protein domain. Methods: Sixty-two USH patients from 46 families with biallelic variants in MYO7A were examined for visual and audiological features. Participants were evaluated based on self-reported ophthalmological history and ophthalmological investigations (computerized visual field testing, best-corrected visual acuity, and ophthalmoscopic and electrophysiological examination). Optical coherence tomography and fundus autofluorescence imaging were performed when possible. Auditory and vestibular functions were evaluated. Patients were classified according to the type of variant and the protein domain where the variants were located. Results: Most patients displayed a typical USH1 phenotype, that is, prelingual severe-profound sensorineural hearing loss, prepubertal retinitis pigmentosa (RP) and vestibular dysfunction. No statistically significant differences were observed for the variables analysed except for the onset of hearing loss due to the existence of two USH2 cases, defined as postlingual sensorineural hearing loss, postpubertal onset of RP, and absence of vestibular dysfunction, and one atypical case of USH. Conclusion: We were unable to find a correlation between genotype and phenotype for MYO7A. However, our findings could prove useful for the assessment of efficacy in clinical trials, since the type of MYO7A variant does not seem to change the onset, severity or course of visual disease.This project was financially supported by the Center for Biomedical Network Research on Rare Diseases (CIBERER), FIS (PI16/00425, PI16/00539 and IIS‐FJD Biobank PT13/0010/0012). LG‐M and IPR were supported by the Río Hortega and predoctoral Programs (CM16/00126 and FI17/00192, respectively) from Institute of Health Carlos III (ISCIII, Spanish Ministry of the Economy, Industry and Competitiveness), Regional Government of Madrid (CAM, B2017/BMD37), and Regional Government of the Valencian Community (PROMETEU/2018/135), with partial support from the European Regional Development Fund (ERDF). Additional support was received from the Ramon Areces Foundation, the University Chair UAM‐IIS‐FJD of Genomic Medicine, ONCE Foundation and the Spanish National Organization of the Blind (ONCE). Drafting of this manuscript was possible thanks to the UshTher project (Clinical trial of gene therapy with dual AAV vectors for retinitis pigmentosa in patients with Usher syndrome type IB), which has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 754848. The authors are grateful to the families that participated in this study and to the colleagues who referred patients to us. We also thank the Genetics and Ophthalmology Departments of Fundación Jimenez Diaz University Hospital (FJD, Madrid) and Asunción Giménez, Cristina Villaverde, and Ignacio Mahillo for their technical assistance

Agreement and differential use of laboratory methods for the detection and quantification of SARS-CoV-2 in experimentally infected animals

Rodents are widely used for the development of COVID-19-like animal models, the virological outcome being determined through several laboratory methods reported in the literature. Our objective was to assess the agreement between methods performed on different sample types from 342 rodents experimentally infected with SARS-CoV-2 (289 golden Syrian hamsters and 53 K18-hACE2 mice). Our results showed moderate agreement between methods detecting active viral replication, and that increasing viral loads determined by either RT-qPCR or infectious viral titration corresponded to increasing immunohistochemical scores. The percentage of agreement between methods decreased over experimental time points, and we observed poor agreement between RT-qPCR results and viral titration from oropharyngeal swabs. In conclusion, RT-qPCR and viral titration on tissue homogenates are the most reliable techniques to determine the presence and replication of SARS-CoV-2 in the early and peak phases of infection, and immunohistochemistry is valuable to evaluate viral distribution patterns in the infected tissues.info:eu-repo/semantics/publishedVersio

Mortality Attributable to Environmental Tobacco Smoke Exposure in Spain in 2020

Introduction and objectives: Exposure to environmental tobacco smoke (ETS) is associated with increased mortality and morbidity. The objective of this study was to estimate the impact of ETS exposure in Spain on mortality in 2020 in the population aged 35 years and over. Methods: A method of estimating attributable mortality (AM) based on the prevalence of ETS exposure was applied. Prevalence data were obtained from a representative study conducted in Spain and the relative risks were derived from a meta-analysis. AM point estimates are presented along with 95% confidence intervals (95% CI), calculated using a bootstrap naive procedure. AM, both overall and by smoking habit, was estimated for each combination of sex, age group, and cause of death (lung cancer and ischemic heart disease). A sensitivity analysis was performed. Results: A total of 747 (95% CI 676–825) deaths were attributable to ETS exposure, of which 279 (95% CI 256–306) were caused by lung cancer, and 468 (95% CI 417–523) by ischemic heart disease. Three quarters (75.1%) of AM occurred in men and 60.9% in non-smokers. When chronic obstructive pulmonary disease and cerebrovascular disease are included, the burden of AM is estimated at 2242 deaths. Conclusions: ETS exposure is associated with 1.5% of all deaths from lung cancer and ischemic heart disease in the population aged 35 and over. These data underline the need for health authorities to focus on reducing exposure to ETS in all settings and environmentsInstituto de Salud Carlos III (ISCIII), reference: PI22/00727, co-funded by the European UnionS

A New tool for the assessment of severe anthropogenic eutrophication in wetlands under increasing human pressure

It is about time the assessment of trophic state in wetlands is no longer estimated through the regressions and thresholds modelled for deep-stratified lakes where sediment nutrient recycling was purposely neglected. We are in badly need of a system trophic indicator to be used as a reference for biological indicators. The recent use of biological communities (macro-invertebrates, diatoms, etc) for the evaluation of the “ecological state” of a water body implicitly requires the assessment of its “trophic state”

Previous SARS-CoV-2 Infection Increases B.1.1.7 Cross-Neutralization by Vaccinated Individuals

With the spread of new variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), there is a need to assess the protection conferred by both previous infections and current vaccination. Here we tested the neutralizing activity of infected and/or vaccinated individuals against pseudoviruses expressing the spike of the original SARS-CoV-2 isolate Wuhan-Hu-1 (WH1), the D614G mutant and the B.1.1.7 variant. Our data show that parameters of natural infection (time from infection and nature of the infecting variant) determined cross-neutralization. Uninfected vaccinees showed a small reduction in neutralization against the B.1.1.7 variant compared to both the WH1 strain and the D614G mutant. Interestingly, upon vaccination, previously infected individuals developed more robust neutralizing responses against B.1.1.7, suggesting that vaccines can boost the neutralization breadth conferred by natural infection.info:eu-repo/semantics/publishedVersio